When a third generation partnership project (3GPP) device or user equipment (UE) desires to access an Evolved Packet Core (EPC)/Evolved Packet System (EPS) core via an access network that is not a 3GPP defined access network (where a 3GPP access network could be a Global System For Mobile Communications (GSM) EDGE Radio Access Network (GERAN), Universal Terrestrial Radio Access Network (UTRAN) or Evolved Universal Mobile Telecommunications Service (UMTS) Terrestrial Radio Access Network (E-UTRAN)), the UE may need to select and then establish a connection with an Wireless Local Area Network (WLAN). Various aspects and predicates exist for a UE to access an WLAN and obtain a list of emergency codes that can be trusted. These may include trusted access, non-trusted access, Extensible Authentication Protocol (EAP), Protocol Configuration Options (PCO), Voice over Wi-Fi, UE detected emergency calls, Dynamic Host Configuration Protocol (DHCP), WLAN Access Network Query Protocol (WLAN ANQP), Fifth generation (5G) network, emergency numbers via WLAN and policy using a Non-Access Spectrum (NAS) indicator via a 3GPP Access Network (AN), or Emergency numbers via 3GPP Access Network.
Networks need to provide emergency numbers and types or categories (e.g. fire, ambulance, police, mountain rescue, etc.) for which “UE detected emergency calls” are supported by the network or public land mobile network (PLMN) via a (Trusted or untrusted) WLAN. Different countries support different emergency numbers and types and categories, and “UE detected emergency calls”. Further, even in the same country, different PLMNs may support different “UE detected emergency calls”.
A UE connected to different PLMNs via 3GPP access and WLAN access may be configured by both (i.e. first and second) PLMNs with emergency call numbers and types or categories.
When the UE has been configured with a second PLMN's emergency numbers and types or categories via WLAN, and the UE uses these to initiate a “UE detected emergency call” via, for example, 3GPP access where the serving network is a first PLMN, then first PLMN may receive a “UE detected emergency call” for a type/category for which it hasn't configured its network.
Instead, the first PLMN would have expected to receive a normal call. The normal call request message would include dialed digits. The network would then parse the dialed digits and possibly route the call to the correct public safety answering point (PSAP) based on the dialed digits. A “UE detected emergency call” request message, however, need not include dialled digits.
Further, when emergency numbers are provided to a UE via WLAN, they may be provided before a UE is connected to a PLMN. When more than one PLMN is available, there is no mapping of emergency numbers to those PLMNs. Alternatively, the entity providing emergency numbers that are provided to a UE via WLAN may not know or may not be able to predict to which PLMN the UE will successfully connect via WLAN. An example of such an entity is an ANQP server or an Access Point (AP).
A fifth generation (5G) network can have many network slices, including but not limited to Internet of Things (IoT), voice, among others. Each slice may have its own set of emergency numbers. For example, one number may be 911 for voice and a second number may be 811 for automated IoT devices. There is no way for a multi-purpose device to know which emergency number to use for a particular slice.